6 



Prof. Victor Horsley. 



[Dec. 11, 



tremors in all the muscles of the body. These tremors soon become 

 clonic spasms, and ultimately paroxysms of true tetanus, as a result of 

 which the animal dies a few days after the operation. 



It is clear then that in dogs the thyroid gland has an intimate con- 

 nexion with the central nervous system. 



In the monkey, excision of the thyroid, just as in the dog, may be 

 followed immediately by fibrillar contractions of the muscles of the 

 extremities, but, as a rule, the animal remains perfectly well for five 

 days. 



The tremor at its first appearance is uniform, and has a wave rate 

 of 8-10 per second. 



In forty-eight hours, as a rule, it becomes paroxysmal, i.e., exhibits 

 recurring exaggerations, the paroxysms being of variable duration 

 and interval, but giving a new character to the tracing, owing to the 

 powerful movements of the limbs, &c. 



The uniform tremor persisting between the paroxysms now has, as- 

 a rule, a wave rate of 16 to 20 per second. 



These symptoms persist, as a rule, about twenty days ; they then 

 decline, the paroxysms disappearing slowly, but ceasing before the 

 constant tremor. 



During the whole of this time there is rigidity and paresis* of the 

 muscles affected. 



Moreover, the symptoms of the disease termed Myxoedema by 

 Dr. Ord, and ordinary cretinism are gradually developed. 

 For— 



The animal becomes gradually more and more imbecile and apathetic, 

 sitting, as it does, huddled up and taking no notice of anything, iu 

 strong contrast to its customary vivacious state. 



It exhibits swellings of the skin of the face, abdomen, &c, due to 

 infiltration of the tissues by mucin. (This change, visible to the 

 naked eye, has been chemically established by my friend Dr. Halli- 

 burton, B.Sc, whose results are published in accompanying table.) 



The salivary glands become enormously hypertrophied, and the 

 parotid gland, which normally secretes a watery, serous fluid, now 

 takes up a muciparous function, f and produces quartities of mucin. 



This increase of function is interesting, as probably offering a clue 

 for further investigation into the physiology of secretion. 



The blood is profoundly changed : there is a decrease of red cor- 

 puscles, and a primary increase of the leucocytes, followed by a 

 decrease, oligemia thus resulting. Moreover, it contains mucin in 

 proportion to the duration of life after the operation, and the serum 

 albumin is diminished. 



* Sometimes almost total paralysis of the extensor muscles. 



f Microscopic investigation shows the cells of the parotid to be swollen by 

 mucinogen (?) and rapidly disintegrating. — 14th December, 1884. 



